Topic outline

    • Water

      Q34. Why during winter more fog occurs in areas where more trees are there?

      Ans. Plants releases water in the form of water vapor into the air through the process of transpiration. This vapor condenses to form fog. Areas where more trees are there, more transpiration will occur and hence there is more formation of fog.


      Q35. List 3 ways to conserve water.

      Ans. Ways to conserve water:

                                i.        Collecting and storing rainwater for later use.

                               ii.        Turning the water off when brushing teeth or washing utensils can save a lot of water.

                              iii.        Using of sprinkler system for watering the lawn.


      Q36. Why monsoon is so important?

      Ans. Monsoon is important because

                                 i.        Most of the rainfall occurs during the monsoon season.

                                ii.        Rains bring relief especially after hot summer days.

                               iii.        Sowing of many crops depends on the arrival of monsoon.

      Q37. Why are rains important to us?

      Ans. Rain is a major component of the water cycle. Many forms of land-based life depend on fresh water, which comes from rain. The rainwater also fills up the lakes and ponds. A part of the rainwater seeps into the ground. Most of this water becomes available to us as ground water.


      Q38. Think and write some more use of water, apart from water used in our daily activities.

      Ans. Other uses of water

                               i.        Plants also need water for photosynthesis. Photosynthesis is what plants do to prepare their food, and water is critical to this process.

                              ii.        Water is used in industries for producing almost all the things that we use.


      Q39. What is spring water?

      Ans. A part of the rainwater collects over the rocks under the earth.

      Sometimes due to pressure, this water naturally comes out of the earth’s surface in the form of a spring from any available opening. This water is called spring water.


      Q40. Why do we see water droplets (dew) on leaves in winter?

      Ans. On a warm day, water evaporates from the warm ground into the air. In night the warm ground continues to radiate heat into the air. As the ground begins to cool, the air will not be able to hold all the moisture. Water vapor in the air will begin to condense. That's why we see water droplets on leaves in winter.

      Q41. What happens if it does not rain for a long period?

      Ans. No, rain for a long period can cause the following:

                                i.        The soil becomes dry.

                               ii.        The level of water in ponds and wells of the region goes down and some of them may even dry up.

                              iii.        The ground water may also become scarce. This may lead to drought.


      Q42. The process of condensation plays an important role in bringing water back to the surface of earth. How does it happen?

      Ans. When the air moves up, it gets cooler and cooler. At sufficient heights, the air becomes so cool that the water vapor present in it condenses to form tiny drops of water called droplets. It so happens, that many droplets of water come together to form larger sized drops of water. Some drops of water become so heavy that they begin to fall. These falling water-drops are called rain.


      Q43. Write a short note on importance of water.

      Ans. Water is one of the most vital substances on earth. All living being need water to survive. Apart from drinking it to survive, people have many other uses for water.

      Some of the most common uses of water are:

                               i.        For drinking.

                              ii.        For cooking, bathing, cleaning and washing.

                             iii.        For irrigation.

                             iv.        For generating steam in boilers.

                              v.        In industries.

                              vi.        For generating hydroelectricity.

      Q44. What are the effects of excess rainfall in an area?

      Ans. Excess of rainfall may lead to many problems. Heavy rains may lead to rise in the level of water in rivers, lakes and ponds. The water may then spread over large areas causing floods. The crop fields, forests, villages, and cities may get submerged by water. Flood cause extensive damage to crops, domestic animals, property and human life.


      Q45. What causes drought?

      Ans. Even if it does not rain in a region for a year or more, the soil continues to lose water by evaporation and transpiration. Since it is not being brought back by rain, the soil becomes dry. The level of water in ponds and wells of the region goes down and some of them may even dry up. The ground water may also become scarce. This may lead to drought.


      Q46. What is rainwater harvesting? Explain the two method of rainwater harvesting.

      Ans. Rain water harvesting is a method used for collection and storage of rainwater into natural reservoirs or tanks for later use.

      The two method of rainwater harvesting are:

                                  i.        Rooftop rainwater harvesting: In this system the rainwater is collected from the rooftop to a storage tank, through pipes.

                                 ii.        Another option is to allow water to go into the ground directly from the roadside drains that collect rainwater.

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